1. Field of the Invention
This invention is related to a machine for deveining shrimp, and, more specifically, to an apparatus for cutting the sand vein from shrimp with improved cutting control and capability to devein shrimp of different sizes.
2. Description of Related Art
Shrimp cutting and deveining machines have existed for a number of years. An early version is shown in U.S. Pat. No. 2,702,921 to Pinney. FIG. 1 is a frontal, right-side perspective view of the shrimp cutting machine in Pinney. A shrimp is fed manually into the machine 1 which holds the shrimp in a stretched out position while it is being cut lengthwise down the center of the back and subsequently cut a second time on each side of the center cut. The shrimp is placed on the top 2 of the machine with its back side up, and is then pushed head-first through guides 3 and 4 until it comes in contact with a pair of rotating flexible rubber disks 5 and 6 which grasp the shrimp, pulling it into the machine.
FIG. 2 is a left-side view of the interior mechanisms of the shrimp cutting machine of FIG. 1. Upon pulling the shrimp into the machine, the flexible disks 5 and 6 press the bottom of the shrimp against the surface of a rotating feed drum 7, thus supporting the shrimp on the bottom and also holding each shrimp in proper position so that a cutting disk 8 can cut the shrimp longitudinally down the center of the back.
The shrimp continues to follow the periphery of the feed drum 7 and is carried past a revolving pair of cutting disks 9 which cut the shell structure on each side of the center cut previously made by the single cutting disk 8. The shrimp is then ejected from the bottom of the machine.
A drive mechanism 11 comprising an electric motor 12 and a chain and sprocket mechanism 13 are used to drive the drum and disks. The placement of the drive mechanism 11, however, makes the Pinney machine extremely difficult, if not impossible, to keep in a clean and sanitary condition. As the shrimp is cut, the sand vein is stripped away, and flying debris and bodily fluids from the shrimp cover the inner workings of the machine. It must be frequently disassembled, cleaned and sanitized to keep the machine in sanitary working condition. Additionally, the use of a feed drum to support the shrimp places severe limitations on the degree of control which an operator is afforded during the cutting process. Shrimp vary considerably in size, and the mechanism in Pinney does not enable rapid adjustment of the cutting depth in accordance with the size and thickness of the shrimp.
Another existing shrimp deveining machine is shown in U.S. Pat. No. 5,290,199 to Morris. FIG. 3 is a frontal, left-side perspective view of the shrimp deveining machine in Morris. Morris discloses an improvement of the shrimp cutting machine in Pinney by creating a more sanitary machine 20 with a closed housing 21 for a motor and drive mechanism (not shown), and by mounting the cutting mechanism 22 externally and covering it with a protective shield 23. Morris, however, utilizes a polycarbonate idler roller 24 similar to the feed drum 7 (FIG. 1) in Pinney to support the bottom of the shrimp during the cutting process. The idler roller 24 freewheels on an adjusting shaft 25 which provides a limited capability to adjust the depth of the cut by rotating an adjusting knob 26 on the side of the housing 21. However, this adjustment is time consuming and cannot efficiently be performed dynamically as shrimp bodies of different sizes are fed through the machine.
It would be advantageous to have a shrimp deveining machine with the sanitation improvements of Morris and the capability to more precisely and dynamically control the depth of cut on each shrimp body as it passes through the machine. It is an object of the present invention to provide such a shrimp deveining machine.